This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Modulated imaging (MI) is a recent technology that uses patterned illumination and non-contact detection to obtain quantitative subsurface images of tissue optical properties over a wide field-of-view. MI is well-suited for the non-invasive study of cancer animal models that can be used to understand the relationship between tissue optical properties and tissue histology and biochemistry. In particular, we are interested in the biological mechanisms of tumor angiogenesis and their alterations from chemotherapy. Two different animal models were studied. In the first model, 13762 MAT-III rat mammary tumor cells were inoculated in the mammary fat pad of female Fisher 344 rats (~160g). The MI instrument acquired tissue optical property images during both tumor growth and treatment (Cyclophosphamide) phases. From these images, the tissue concentrations of oxy-hemoglobin, doexy-hemoglobin, and water were quantified. Tissue scattering parameters were also determined. In a second model we imaged p53/brca1 mutated transgenic mouse tumors under cisplatin treatment (5mg/kg daily for a week). During the MI measurements, hyperoxic gas intervention was also applied as a contrast to detect tumors and to monitor chemotherapeutic effects. These studies are so far very preliminary and the results obtained from MI need to be confirmed by immunohistochemical analysis. However, we have found great potential from the results of these animal models that can be applied to clinical cases.